I have 39.5x18x15 Boggers on allied beadlocks and 39x15x15 TSLs on steel non beadlock rims. Not sure on the difference in rim width at the moment but could this combo work? Both in the width of the tire and having non beadlock front rims on the TSLs and beadlocks on the rear Boggers?

I wheel in the Midwest and it seems to be a combo alot of guys use for rock and also the mud boggers too!

How common would you say it is to do the TSL front / Boggers rear combo?
Best of both worlds for mud/rock/lateral stability/drivetrain longevity?

I have only wheeled at the Badlands in Attica, IN but I know that Boggers are the king of the mud but with rocks thrown in probably good to do the TSL/Bogger combo!

When I lived in northern California I loved my 37x12.5x15 GY MTRS on my built XJ and many people ran those tires for the Rubicon and other rock crawling trails there although the TSL SX tires I have seen too and are very tough!

i always herd people did this because tsls get less traction in mud and are less likely to put a hurting on your front driveline. not sure how true that is but it is a common setup.

and i second the stl sx! my next tires will be sxs or pb rockers

Around here, yeah, that was pretty common. While everyone has alloys and dana 60s these days, there weren't always good options. Lots of people ran 38-44s in Jeeps and broncos on front dana 44s. You were limited with 30 spline outers, stock hubs, etc. So it was common to run a LSD instead of a locker, and less aggressive TSLs in the front.

I ran SSRs front/boggers rear in my CJ5, which was a nice combo for running mud and anything that needed floatation.

I don't like boggers for trail use thats going to see a lot of off camber, they walk sideways way too much.

By far, my favorite all around tire is a swamper SX, with cut treads (in the pattern that I've posted here before). I've run them like this in 36 and 38.5 sizes on beadlocks usually around 4-7 psi, and they are very good for the terrain around here.